Muffler attachment for telephones



D. PETRl-PALMEDO. AMUTFLER ATTACHMENT TOR TELEPHONES.

APPLICATION FILED MAY 27, 1920.

.Patented Mar. 22, 1921.

3 SHEETS-SHEET I.

D. PETRl-PALMEDU.

MUFFLER ATTACHMENT FOB TELEPHONES.

APPLICATION man MAYN, 1920.

.1, 372, 1 62. A Patented Mar. 22,-1921.

3 SHEETS-SHEET 2.

D. PETRI-PALMEDO. MUEFLER ATTACHMENT EUR TELEPHONES.

AFPLICATTON FILED MAYZTl 1920. 1,372,162. Patented Mar.22,1921.

3 SHEETS-SHEET 3.

UNITED STATES PATENT OFFICE. i

DAVID PETRI-PALMEDO, OFVBRIDGEPORT, CONNECTICUT, ASSIGNOR TO MUFFLER PHONE MFG. CO., INC., OF MERIDEN, CONNECTICUT, A CORPORATION.

MUFFLER ATTACHMENT FOR TELEPHONS.

Specification of Letters'Patent.

Patented Mar. 22, 1921.

Application filed May 27, 1920. Serial No. 384,703.

To all whom t may concern:

Be it known that I, DAvID Perm-Par.- Mnno, a citizen of the United States, .residing at Bridgeport, in the county of Fan-field and State of Connecticut, have invented a new and useful Improvement in Muflier Attachments for Telephones; and l de hereby declare the following, whentaken in connection with the accompanying drawings and the characters of reference marked thereon, to be a full, clear, and exact description of the same, and which said drawings constitute part of this application, and represent, in-

Figure 1, a face view of a mufiler attachment for telephones, constructed 1n accordance with my invention.

'Fig 2, a side view of the same shown as attached to a telephone.

Fig. 3, a front View of the rear plate and diaphragm.

Fig. 4, avertical sectional view of the muffler attachment.

Fig. 5, a face view of therrear plate detached.

Fig. 6, a rear view of the front plate detached.

Fig. 7, a face view of the diaphragm detached.

Fig. 8, a face view of'one of the linings detached.

Fig. 9, a side View, partly in section, of a modified form of my invention.

Fig. 10, a sectional view on the line 10-10 of Fig. 9.

This invention relates to an improvement in muffler attachments for telephones, the obj ect being to permit the use of a telephone in the presence of others without being overheard and furthermore to so increase the sound for the transmitter -that usual speaking tones may be readily heard; and the invention consists in the construction and arrangement of parts as hereinafter described and particularly recited in the claims.

In one form of my invention, this device takes the place of the ordinary conical transmitter of a telephone instrument and consists of a transmitter 15 having a screw threaded stem 16 for connection with the usual telephone instrument 17. This transmitter is formed integral with a plate-like member 18 which is formed on its inner face with a series of outwardly projecting studs 19 having reducedends 20 to enter sockets 21 formed in a front plate 22 corresponding in diameter to the plate 1S and separated therefrom by the studs. The outer plate 18 is formed with a collar 23 to which a mouthpiece 24 is connected. this mouth-piece being so formed that it will inc-lose the lips of the person speaking, yet leave them perfectly free to move.

Arranged centrally between the plates is a diaphragm 25 of felt, having clearance holes for the studs 19 by which it is held in place, Vand formed withk a central opening 26 for the insertion of the inner end of a rear defiector 27, to the outer end of which is fixed a front deflector 28, these two deflectors forming a direct channel from the mouthpiece to the telephone. The diaphragm 25 is held in position by inwardly projecting lugs 29 and 30 formed in the adjacent faces of the plates. The diameter of the diaphragm is less than the diameter of the plates, which are formed near their outer edges with annular channels 31 and 32. Against the inner face of the outer plate is a lining 33 and against the forward face of the inner plate is a corresponding lining 34 held in place by the studs 19 and lugs 29 and 30.

The space around the deflector opens into a space between the diaphragm and the lining, forming a contracted passage to the channels 31 and 32 and to the space left between the adjacent edges of the plates. With this construction, the sound-waves have a straight passage to the diaphragm of the transmitter. In speaking into a closed receptacle, considerable air pressure is created and this is relieved by the passage around the deflector and outward between the plates, this passage being loosely sealed by the edges of the felt diaphragm and linings so as to break the sound-waves but permit the escape of air.

While it is generally desirable to form the rear plate with the conical transmitter for attachment to the telephone, it is sometimes desired to apply a muffler attached to the mouth-piece of a telephone, as shown in Figs. 9 and 10, and for this purpose, I form the back plate with an annular collar 35 in place of the conical transmitter 15 and in the bottom of the collar is an annular groove 36 in which a packing-ring 87 is placed to receive the edge of an ordinary mouth-piece 38 to which it is attached by placing balls 39 around the outside of the mouth-piece,- theV balls being held by a cap 40 locked with the collar by a spring-ring 4l located 1n grooves formed in they adjacent faces of the ring and sleeve, the cap having an inwardly projecting flange l2-formed with cam surfaces 43 by which 'the balls are crowded against the edge of the mouth-piece.V

Iclaim: v Y

Vl. A mufier attachment,` for telephones, comprising two plates one' adapted to be connected with a telephone and the other provided with a mouth-piece, a diaphragm located 'between said plates, a two-part de-Y flector mounted in said diaphragm and forming a direct opening, and linings applied to the adjacent faces of the plates.

said Lplates,` va two-part deflector mounted in the center' of said diaphragm, -and linings applied to the inner faces of the platesand forming passages between the plates and diaphragm for the escape of air between the the other plate whereby the plates are spaced apart, said plates formed near their outer edges with annular channels,*a-diaphragm located centrally between the plates7 a two-part deiector mounted in the center .Y

ofrs'aid diaphragm and forming laV direct Vopening' through the muffler, and linings applied tothe inner faces of the said plates and forming air passages between the plates to the outer edges thereof." 'f

In Atestimony whereof, I have signed Vthis specification in the presence of two subscrib-Y ing witnesses. z'

' DAVID lETRI-PALMEDU.

Witnesses:V 1 Y Y R. M. (LASPARINO,v I. J'. POCHER. 

